How Does Urine Adulterants Affect Urine Drug Testing
You may not need a forty five dollar bottle of "pass the test" stuff to cheat a drug test. Can a few drops of clorox bleach help you keep your job?

C common adulterants may disrupt or alter immunoassay reaction, therefore results in false negative or "invalid" test results. If used technically, clorox bleach may full the test by causing a false negative result, a negative results of a urine containing high concentration drug.

 There are many adulterant products intended to disable urine test products.

The most commonly used urine drug test products are rapid test or lateral flow test products. The basic component of a rapid test is a test strip held in a plastic container, a cassette, a card, or a cup, that facilitates access of urine specimen to the test strip. The test results are visually read in a section of the test strip. The presence or absence of a colored test (T) line indicates a negative or positive test result. A control (C) line, which indicates the test is correctly performed should always present.

There are two categories of adulterants. The first kind is urine substitute or fake urine. Urine substitute contains normal urine substances, such as pH buffer, sodium chloride, creatinine, protein, bilirubin, etc. The second category of adulterants include chemicals intended to disable or lower the sensitivity of drug tests. Commonly used adulterants include nitrites, peroxides, bleach (Hypochlorite), and cross-linking agents (glutaraldehyde), etc. These chemicals affect drug test by altering the reaction environment or the active ingredients, enzymes, antibodies, or drugs of interest.

The objective of the following experiment is to investigate how common adulterants interfere with rapid drug tests.

Interferents Study


This study is to investigate if common adulterants interfere with rapid urine drug tests. If they do, how and at what concentration they affect the assay outcome.



Vendor/Catalog No.

Lot No.

Starting Concentration

Sodium Nitrite








Glutaraldehyde 8%




Sodium Hypochlorite (4-6%)




Hydrogen Peroxide, 50wt%




Hydrochloric acid Sigma   5N

Human Urine

Hycor, KOVA-Trol III



CardLab, CupLab, and POC devices for testing THC, methamphetamine, BZD, Opiate (morphine), and Cocaine (bezoylecgonine)


  1. Reconstitute Normal Urine prep in accordance with product manual from HycorP/N91017-03E, 5/04.
    1. Add 60ml of d.i. water into the bottle and mix well.
  2. Prepare 2ml of Starting solutions by mixing the interferents with Human Urine.
  3. 1:10 dilute the starting solutions with Normal human urine till 1:1000 by mixing 0.2ml of high concentration solution with 1.8ml urine.
  4. Negative specimen testing: test five drug strips with the preps.
    CardLab, CupLab, and POC devices containing THC, MET, BZD, OPI, and COC test strips are to be used for testing.
  5. Positive specimen testing: Spike 1.5 x cutoff level drugs (PCP, THC, MET, MOR, BZD, COC, BAR) into the preps from step 2 and 3. Test the drug positive solutions with rapid drug test devices.



Similar results were found with all test devices.


Sodium Nitrite upto 100mg/ml, Creatinine upto 10mg/ml did not affect the test results of either negative or positives samples.


Glutaraldehyde and Sodium Hypochorite: At concentration > 0.2%, the substances caused "invalid" test results (Fig 1). At lower than 0.1% concentrations, neither substance had any effect on the tests. No false negative or false positive results are produced by urine samples spiked with such adulterants.


Adding Clorox into drug positive urine sample may fool the test by resulting in a false negative test result. However, the job must be technically done. Too little Clorox won't help, while too much will bleach everything out causing invalid test result.

Fig. 1. Clorox in Drug Negative Sample

Fig. 2 Clorox in Drug Positive Sample

Fig. 3 Two high concentration adulterants disrupt immunoassay reaction. 0.4% of Glutaraldehyde and 0.25% Sodium hypochlorite, when tested with POC test devices resulted in partial or total absence of both C and T lines. The CardLab devices tested with higher concentrations, 4%, and 2.5% of adulterants exhibited total disruption of the assay reaction.


Fig. 4. At lower concentrations, the adulterants do not cause false negative results.

Hydrogen Peroxide: At 25%, the substance caused false negative results for all five drug tests. At 12.5%, the substance had no effect on any of the tests.

Hydrochloric Acid: 0.1N HCl (1drop 5N HCl in 2ml control sample) caused weak false negative result in the positive sample tests. 0.2N-1N HCl in the same positive specimen increasingly resulted in weaker control lines till the test results became "invalid".


Adulterants affect immunoassay reaction through denaturing antibodies, colloidal gold labels, and disrupt antibody-drug binding reaction.

At certain concentrations, certain substances cause false negative test results in some drug tests. Only carefully formulated adulterants will work in some drug tests.

Future Study

More data is being collected and analyzed in this ongoing adulterant effect study. This webpage will be updated with more information.


Thank you very much for visiting. Please email your comments or questions to


Thanks to Ms. Jian Yang for her generous contribution to this study.



Dr. Tony Tusak of Acro Biotech is conducting adulterant testing work.